Continuous casting installations

ABSTRACT

The continuous casting installation according to the present invention comprises a tank for receiving the liquid material to be cast communicating with at least one diestock positioned between said tank and extractor means, said diestock being subjected to the effects of cooling means capable of solidifying said material in a zone of the diestock termed the &#39;&#39;&#39;&#39;solidification zone.&#39;&#39;&#39;&#39; The diestock is so devised as to be capable of remaining in communication with said tank at the same time as it is shifted longitudinally in relation to other stationary parts of the installation, in the direction of advance of the material being cast, and of then being held immovable in its new position by suitable control means.

United States Patent Inventor Appl. No.

Filed Patented Assignee 'Priority CONTINUOUS CASTING INSTALLATIONS 4 Claims, 1 Drawing Fig.

US. Cl 164/281, 164/260, 164/283 Int. 822d 11/10 FieldolSearch 164/82,83,

Primary Examiner-R. Spencer Annear Auorney Larson, Taylor and Hinds ABSTRACT: The continuous casting installation according to the present invention comprises a tank for receiving the liquid material to be cast communicating with at least one diestock positioned between said tank and extractor means, said diestock being subjected to the effects of cooling means capable of solidifying said material in a zone of the diestock termed the solidification zone. The diestock is so devised as to be capable of remaining in communication with said tank at the same time as it is shifted longitudinally in relation to other stationary parts of the installation, in the direction of advance of the material being cast, and of then being held immovable in its new position by suitable control means.

INVENTOR ATTORNEY CONTINUOUS CASTING INSTALLATIONS The present invention relates generally to continuous casting installations, that is to say installations comprising atlease one diestock fed at one end with material in the liquid state which is cooled in this diestock by suitable cooling means to below its solidification temperature and is ultimately extracted at the other end of the diestock in the form of a solid extrusion the section of which matches that of the hold in the diestock, the direction in which the material to be cast is fed being either vertical, horizontal, or oblique, and there being no restrictions as to the nature of the material provided only that it lends itself to the process of continuous casting, as is the case notably with many metals, alloys and plastics.-

The invention likewise includes in its scope the extruded sections obtained in such continuous casting installations.

Before describing the principal features of the present invention, it may well be opportune to draw attention to a delicate problem inherent in the very principle of continuous castingand to recall the imperfect solutions proposed heretofore for overcoming it.

It has been found that the part of the diestock in which solidification of the material being cast takes place tends to deteriorate fairly quickly, resulting in a scored and irregular surface on the extrusion and impairing furthermore the extrusions ability to slide, in some cases to the extent even of causing the extrusion to break when the solidification zone in the diestock is seriously damaged.

In an attempt to circumvent this disadvantage and thereby extend continuous casting runs, it has been suggested that during the casting run the solidification zone be shifted towards the inlet end of the diestock, i.e. towards the end into which the liquid material is fed, since this end will obviously not yet exhibit substantial wear when the diestocks solidification zone is already damaged.

lt has accordingly been proposed notably,

to reduce the temperature of the liquid material to be impelled through the diestock, which is possible only to a limited extent because of the need to maintain a temperature above the solidification temperature and which leads moreover to a waste of heat at the start of the run and can adversely affect the initially chosen optimum values of the solidification parameters in the particular case being considered,

or to increase the effectiveness of the cooling means associated to the diestock, which however often raises tricky technological problems, necessitates greater expenditure of energy in any event, and has the added disadvantage of adversely affecting the solidification parameters as before,

or to reduce the rate at which the section is extruded, which obviously reduces the efficiency of the installation, could jeopardize the profit-earning capacity of the installation because of diminished production, and again adversely affects the solidification parameters,

or else to modify the distance between the cooling means and the containment means for the material kept in the liquid state, which yet again has an unfavorable effect on the solidification parameters.

Thus, the various solutions proposed heretofore for mitigating damage to the diestock all have disadvantages. in particular that of adversely affecting at least some of the initially chosen optimum values for the solidification parameters relevant to the material in question, and an attendant deterioration in the quality of the extruded sections obtained.

lt is the object of the present invention to provide a way of overcoming this problem of diestock deterioration that has none of the drawbacks inherent in prior art solutions and notably avoids detrimental effects on the optimum values for the solidification parameters, and the present invention accordingly relates to continuous casting installations comprising a tank for the liquid material to be cast that communicates with at least one diestock positioned between said tank and an extractor device and subjected to cooling means capable of solidifying said material in a zone of said diestock hereinafter referred to as the solidification zone, said diestock being so devised as to be capable of remaining in communication with said tank at the same time as it is shifted longitudinally in relation to other stationary parts of the installation, in the direction of advance of the material being cast, and of then being held immovable in its new position by suitable control means, whereby a shift of said diestock of appropriate amplitude in said direction results, without modification to the values of the solidification parameters, in the diestocks solidification zone being transferred to a region which was theretofore in contact with the liquid material and has therefore not yet suffered deterioration.

In addition to this main provision, the invention includes a number of other features preferably used at the same time, to which more explicit reference will be made hereinafter.

The description which follows with reference to the accompanying nonlimitative exemplary drawing will give a clear understanding of how the invention can be carried into practice.

The single figure in the accompanying drawing shows diagrammatically in side elevation a continuous casting installation devised in accordance with the present invention. The continuous casting installation shown in the drawing is intended to permit continuous casting of a metallic extruded form such as a round bar 1 made of cuprous alloy. As shown in the drawing, such an installation includes the following component parts:

a tank 2 for receiving the metal to be cast, in the form of a liquid bath 3, which metal is preferably conveyed thereinto in the molten state;

at least one diestock 4, arranged vertically in the exemplary embodiment illustrated and gravity fed with molten metal from the bath 3, whereby the metal consequently travels downwardly through said diestock;

a cooling system 5 associated to diestock 4 and based on the circulation of a cooling fluid, for instance;

an extractor device 6 mounted downflow of diestock 4 and exerting a pull on round bar 1.

In accordance with the present invention, diestock 4 is devised in such manner that, at the same time as it remains in communication with liquid bath it be capable of being shifted longitudinally in the direction of advance of the molten material and the bar 1 (Le. downwardly in the specific example herein illustrated), and of then being held immovable in its new position, all other component parts of the installation keeping their positions unchanged.

Preferably, to this end the bottom of tank 2 embodies a passageway therethrough equipped with leaktight means permitting sliding motion of diestock 4, and said diestock is caused to be operable by lockable or irreversible control means preferably of the continuously variable type (as opposed to control means providing preset positions), enabling the diestock to be moved in the required direction (downwardly) and to be held stationary in its new position, said control means consisting for instance of a rack 7 supported on diestock 4 and meshing with a driving pinion 8 adapted to be driven by an irreversible mechanism (such as a worm and skew gear) in such manner that the diestock is automatically restrained in the different successive positions it is made to occupy.

With a continuous casting installation as hereinbet'ore disclosed, the diestock 4 must be in its uppermost position at the start of the casting run and be periodically lowered as the run proceeds whenever the zone of the diestock in which solidification takes place threatens to become damaged (which can be ascertained by examining the surface condition of the extruded sections issuing from the diestock), the diestock being lowered to the extent required to transfer said zone to an ad jacent region further upflow" that is still undamaged.

A continuous casting installation devised in the manner described hereinabove offers numerous advantages, outstanding among which are the following:

longer life for the diestock and the possibility of using it over a greater part of its length;

easy and rapid replacement of the diestock between two casting runs;

improved overall efficiency;

the possibility, should the extrusion break inside the diestock, of inserting a dummy starting bar and of then raising the movable diestock together with the starting bar in order to melt the portion of the extrusion remaining in the diestock together with the top of the starting'bar to enable it to be welded, this being accomplished without damaging the intact part of the diestock (in contrast to what would happen if the portion of the extrusion remaining in the diestock were to be upset towards the molten metal);

and the possibility, throughout the casting run, of maintaining the solidification parameters at optimal values (notably the bath temperature, the extraction rate and the cooling conditions), thereby ensuring constancy in the quality of the end product, notably in regard to its surface condition and its uniformity.

Although it was assumed in the exemplary embodiment hereof that the casting installation comprised only one diestock, it will be manifest that it could include a plurality thereof, which could be moved individually, in groups, or together.

It goes without saying that many changes and substitutions of the parts may be made in the specific embodiments of the different component parts hereinbefore described without departing from the scope of the invention, and that broadly speaking the invention encompasses all alternative constructional forms, and more particularly such continuous casting installations according to this invention, i.e. comprising a movable diestock, including in addition means for operating on certain at least of the parameters relevant to solidification.

What I claim is:

1. A continuous casting device comprising: reservoir means for holding the liquid material to be cast; die means in liquid communication with said reservoir means; cooling means adjacent said die and positioned to solidify liquid material in said die at a solidification zone in said die; extractor means for removing cast material from the die; means for shifting the position of said die from a first position to a second position in a direction longitudinally of the cast material without disturbing the position of said reservoir means and said cooling means and for shifting the position of said die from said second position to a further position in said direction without disturbing the position of said reservoir means and said cooling means; whereby each shift in the position of said die in said direction results, in the absence of any modification of other casting parameters, in a region of the die which was not previously adjacent said solidification zone being transferred to said solidification zone, said region being free of casting deterioration of the type prevalent in a solidification zone, said solidification zone remaining stationary with respect to said reservoir means and to said cooling means.

2. A continuous casting device according to claim 1 further including means for locking said die in said first and further positions 3. A continuous casting device according to claim 1 wherein said shifting means are irreversible 4. A continuous casting device according to claim 1, wherein said shifting means are of the continuously variable type. 

1. A continuous casting device comprising: reservoir means for holding the liquid material to be cast; die means in liquid communication with said reservoir means; cooling means adjacent said die and positioned to solidify liquid material in said die at a solidification zone in said die; extractor means for removing cast material from the die; means for shifting the position of said die from a first position to a second position in a direction longitudinally of the cast material without disturbing the position of said reservoir means and said cooling means and for shifting the position of said die from said second position to a further position in said direction without disturbing the position of said reservoir means And said cooling means; whereby each shift in the position of said die in said direction results, in the absence of any modification of other casting parameters, in a region of the die which was not previously adjacent said solidification zone being transferred to said solidification zone, said region being free of casting deterioration of the type prevalent in a solidification zone, said solidification zone remaining stationary with respect to said reservoir means and to said cooling means.
 2. A continuous casting device according to claim 1 further including means for locking said die in said first and further positions.
 3. A continuous casting device according to claim 1 wherein said shifting means are irreversible.
 4. A continuous casting device according to claim 1, wherein said shifting means are of the continuously variable type. 